In 138 B.C.the emperor of the Han dynasty sent Zhang Qian, an army officer, into central Asia to bring back information about a nomadic tribe with whom the emperor wished to form a military alliance. At this time China was very isolated; between its sharp mountain ranges and the building of the Great Wall, it had almost no relations with the outside world. Zhang Qian’s journey was thus a landmark in Chinese history.

Zhang Qian’s mission failed to create a diplomatic or military alliance, but it had much greater unintended consequences. His reports of previously unknown lands and peoples—and those peoples’ commodities—aided the development of trade relations. Zhang Qian’s route became the first leg of the famous “Silk Road” trade route that ultimately led from China to the Roman Empire. Although many goods were traded on the Silk Road, the Roman demand for Chinese silk yielded the most notable profits.